How many terminals are there on the deadman switch? There should be four wires going to it...one on terminal 1 and one on terminal 2, then one on terminal 7 and one on terminal 8. The ones on terminal 1 and 2 are for the auxiliary and travel and the ones on terminal 7 and 8 are for "pulse reset". This keeps the scr's from turning all the way on if there is a problem with the other half of the switch, like if terminal 1 and 2 short and the pedal is not down to enable travel. Check there and also at the plugging relay on the contactors.